What's with these emails about my classified add? Seems like a scam.

I have got four or five of these emails and I just got these two today, I know somehow this is some sort of scam, Anybody know what the deal is? Anybody else get these about a classified add you have placed?

Dear,am FREEMAN BOB the director of (SUCCESS AUTOLAND).i was into yourpage of advert,where i got your car place on advert for sale and iwill also like to ask if available.

if available there is a client of mine who is much intrested inpurchasing your car and his willing to pay $3,700.also paying withcertisfied check,if this mode of payment is well with you mail meback asap.BEST REGARD,freeman.

This is the latest one I have gotten.

GooD Day,I saw this your ads.(ITEMS). I am located in Holland, and i am interestedin buying this ads and i want you to let me know the present condition ofit and the last price you want to sell it. Payment will bethrough a certified check . Get back to me asap.I need your quick responseThanks....